Although organic compounds have been generally considered to be insulating materials, researches are being energetically conducted in order to discover an organic compound having electrical conductivity. As an organic electrically conductive compound, there is known a charge-transfer complex in which an electron donor and an electron acceptor are bonded to each other due to charge transfer between these two members.
It is already known that complexes obtained by reacting a variety of electron acceptors with compounds having a thiafulvalene skeleton such as tetrathiafulvalene (TTF), tetramethyltetrathiafulvalene (TMTTF), bisethylenedithiotetrathiafulvalene (BEDTTTF), etc., exhibit relatively good electrical conductivity [a Japanese periodical "Kagaku Sosetsu", Vol. 42, page 59 (1983)].
However, among the above electron-donating compounds having a thiafulvalene skeleton, TTF has the following defect: It is inferior in thermal stability due to its low melting point of 115.degree. to 119.degree. C. and cannot be applied to a part exposed to a high temperature, and the area for its use is hence limited. TMTTF and BEDTTTF have excellent thermal stability over TTF, but have the following defect: these compounds have no sufficient electron donating nature, and cannot form a complex when only directly mixed with a generally used electron acceptor, and it is required to employ a complicated method such as an electrolytic crystallization method, or the like, in order to form a complex.
As described above, no organic compound has been found so far which has good electron donating nature, the capability of directly forming a complex with an electron acceptor and excellent thermal stability.
Therefore, it is a first object of this invention to provide a novel organic compound having good electron donating nature, the capability of directly forming a complex with an electron acceptor and excellent thermal stability.
Further, it is a second object of this invention to provide an electrically conductive complex containing, as an electron donor, a novel organic compound having good electron donating nature, the capability of directly forming a complex with an electron acceptor and excellent thermal stability.